HISTORY OF THE ROTIFERA, OR WHEEL ANIMALCULES. 487 
mined separately, is of a yellowish or olive colour, composed 
of granules. Old cases have their surface studded with mi- 
nute parasites, both plants and animals, as Confervas, JDiatoma- 
cece, Podopliryce, and other extraneous matters, even to the 
summit. By picking the case to pieces with the points of needles 
under a low-powered dissecting microscope, I have been enabled 
easily to extract the animal ; it is often hurt by the process, 
but generally it is sufficiently whole to display the internal 
organization, which, owing to the opacity of the case, cannot 
otherwise be discerned. It exhibits no peculiarity, however, 
that calls for notice here. 
The eggs are laid within the case, as I have described and 
figured in the Floscules ( vide supra, p. 166, Plate IX.) ; nor do 
they importantly differ from those of that genus, except in 
then shape, exhibiting a longer ellipse. This lengthened form 
appears to be characteristic of Melicerta (at least I have found 
it in all the species whose eggs I have examined), and to be 
peculiar to it. 
On certain occasions I have, however, found eggs of a vei’y 
different figure and appearance, which I have reason to believe 
would have produced male animals, probably of peculiar form. 
On these eggs, and on the development of the young, I have 
communicated some observations to the Microscopical Society, 
which may be of sufficient interest to be repeated here. 
Opening one or two cases of Melicerta ringens, I freed one 
and another very curious egg-hke bodies, not symmetrical in 
shape, being much more gibbous on one side than the opposite, 
and measuring 1 -1 50th by 1 -260th of an inch. Each was encircled 
by five or six raised ribs, running parallel to each other longi- 
tudinally, somewhat like the ribs ( varices ) that adorn the beau- 
tiful shells known as wentle-traps. Viewed perpendicularly to 
the ribs, the form is symmetrical — a long, narrow oval. The 
whole surface between the ribs appeared punctured or granu- 
late, and the colour was a dull brownish yellow. Under pres- 
sure this egg was ruptured, and discharged an infinity of atoms 
of an excessive minuteness, but every one of which, for a few 
seconds, displayed spontaneous motion. Their whole appear- 
ance, and the manner in which they presently turned to motion- 
less disks, were exactly the same as of the spermatozoa, which 
the male eggs of other Rotifera contain, except that these 
were more minute than usual. 
Prom another case I extracted an egg of the ordinary form 
and appearance. It was very long in proportion to its width, 
measuring l-145thby l-390th of an inch. The contained embryo 
was well advanced ; two red eyes were plainly seen, both by 
reflected and by transmitted fight; the mouth ( mastax ) was 
transverse, very large in proportion, and the jaws worked 
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